#1  
Old 09-18-2020, 10:11 PM
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Scarebird Scarebird is offline
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Default Muffler mod HP loss?

My 1998 Z28 has 38k and did have the restrictive stock exhaust. I replaced it with the Hooker Blackheart setup. While it did free up power, the sound is quite loud. I note the the "mufflers" just before the exhaust tips are straight thru design, 6" round and 12" long in the body.

I am wondering how much restriction loss will be realized if I drive in a blockage, forcing the flow to go thru the packing? I would machine an expansion plug to be an interference fit, welding a nut on so if it does not work as intended I can use a slide hammer to remove. This dam would go halfway into the muffler.


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  #2  
Old 09-20-2020, 11:43 AM
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amcmike amcmike is offline
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I think that's just going to act like a cork. Instead, try putting temporary plugs at the end of the straight portion in each of the dual exhaust tips, thus forcing the exhaust to make a turn after the muffler and out a smaller orifice. This would likely reduce the sound without appreciable impact to flow, plus the dead volume due to the other tip being blocked off, might act as a J-pipe to reduce any resonance.

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  #3  
Old 09-20-2020, 03:38 PM
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Not really - Dynomax did this with their VT series muffler; you build up enough pressure and the flap opens up.



I tried another course: I fabricated a pair of twisted inserts, the idea being the sound will reflect off the twist into the batting while the exhaust continues it's merry way.

Pre-twist the dB level was averaging 69, after the insert 67. The twist was only one turn, my guess is if I get 2 over a foot it would reduce more.



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